Project Abstract Millions of individuals across the United States lack stable housing, including the more than 2 million who become homeless each year. Policy solutions generally oscillate between treatment and prevention. The goal of this study is to evaluate the impact of temporary financial assistance for those at risk of homelessness on health outcomes and healthcare utilization. This study will exploit the quasi-random variation in the allocation of temporary financial assistance at one of the nation's largest call centers?the Homelessness Prevention Call Center (HPCC) in Chicago?to determine how this assistance impacts these outcomes. Based on preliminary results, temporary financial assistance significantly decreases the incidence of homeless shelter entry. Knowing this, the PIs now will extend this analysis to examine the impact of financial assistance on health outcomes for this vulnerable population. The PIs will test the hypothesis that those receiving temporary financial assistance are less likely to visit the emergency department or be admitted to the hospital. This project is the first quasi-experimental study to examine the impact of homelessness prevention on health outcomes and healthcare utilization. While the gold standard in impact evaluation is a randomized controlled trial study, in homelessness policy this is challenging for researchers because the population being served is both extremely vulnerable and highly mobile. These factors make keeping track of recipients of programming difficult and costly. Consequently, there is only limited information about the impact of homelessness prevention programs. Thus, this study fills an important gap in the literature on the effect of homelessness prevention programs. This study is possible because of the unique way in which the HPCC connects eligible callers with financial assistance, and because of information on health outcomes available through administrative data that can be linked to call center data. This study will be informative not only to scholars who study prevention programs, but also to policymakers and program managers who struggle to decide how best to distribute limited resources among prevention and treatment services to address the issue of homelessness. These policy decisions are typically not guided by evidence, because information on the effect of these options is so limited. Currently call centers like the HPCC are accessible by more than 90% of the US Population, including parts of all 50 states, Washington, D.C., and Puerto Rico. Together these centers process more than 15 million calls each year. Thus, the findings of this study will be transformative for policymaking and programming in this area, potentially affecting millions of people. This study will allow policymakers to make more informed choices when allocating limited resources to reduce homelessness, putting resources towards the most effective programs. In addition, this study will examine how this prevention service impacts different types of recipients, so the results will importantly inform service providers who run these call centers. Providers can make more informed choices, targeting emergency funding to those most likely to benefit from them. Importantly, this study will improve research and policy understanding of the impact of homelessness prevention on the health outcomes and healthcare utilization of this at risk population.